THEORETICAL MODELING OF A DIRECTLY HEATED SOLAR-DRIVEN CHEMICAL REACTOR

A theoretical formulation for calculating the performances of a solar-driven catalytic chemical reactor was developed. It accounts for the spatial distribution of the deposition of primary energy within the receiver, the heat transfer into the catalytic bed and the thermochemical endothermic reaction, chemical composition and flow distribution within the reactor. The theory set forth was applied to analyze results obtained in a solar furnace with a directly heated U-shaped tubular reactor, wherein catalytic carbon dioxide reforming of methane occurred. We find that the receiver/reactor assembly acts as a self-regulating system. Beyond a fractional catalytic bed length of 0.14, solar energy can be converted primarily into chemical enthalpy. The fluid temperature gradient monitors the heat balance by adjusting the overall rate of conversion to the rate at which energy is being transferred through the reactor walls. Under certain circumstances, the process may be heat-transfer limited or controlled by chemical thermodynamics. A good fit between theory and experiment and accountability of all the intricate details in the various calculated performances of the receiver/reactor system support the theoretical model set forth in this study. We offer it as a tool for simulating future experimental results and for designing solar-driven reactors. © 1990.